My Mum had a similar experience with Spenser last night. I was on the phone downstairs, and as soon as I was free Mum said I muts come and look at Spenser becuase he had flopped on his side and looked 'strange.' I must admit he did look rather lifeless, and his eyes were tight shut, but he sat up when I went to stroke him.
Later that night he flopped on his back with all four legs stuck up in the air - I would have been seriously worried if I hadn't seen him doing it! :shock: